Facilities utilizing electric cranes (e.g., ports (ocean and inland), rail yards, industrial facilities) can experience problems relating to the grid power required to operate the cranes. In some locations there are limits on the available power that can be drawn from the grid due to the local energy infrastructure. This limitation of available grid power can hinder expansion of the business operation or upgrades to other equipment. Other locations that have the infrastructure to supply enough grid power to handle peak equipment loads charge a premium when this power demand is used resulting in higher facility operating costs.
Electric cranes can develop regenerative energy due to operations such as lowering a load or slowing down crane functions. The typical electric crane has resistors for the purpose of dissipating this energy as there is no energy storage system on the crane and the typical grid utility does not allow the energy to be returned. The regenerative energy is wasted in the resistors, and this is accepted as such power dissipation prevents damage to the controls due to excessive voltage and heat that would otherwise be created by the regenerative energy. There are devices that attempt to transfer this energy from crane to crane, but this strategy is dependent on the availability of the energy from one crane and the need for energy from another crane.